1. Technical Field
The present invention relates to novel diagnostic methods and kits for colorectal cancer (CRC). More specifically, the present invention relates to diagnostic methods, comprising the steps of; a) identifying recurrently altered regions (RAR) on chromosome; and (b) detecting genomic alterations in RAR.
Also the present invention relates to kits for prognosis assessment of colorectal cancer (CRC) and novel tumor suppressor genes for diagnosis of colorectal cancer (CRC).
2. Background Art
Colorectal cancer (CRC) accounted for about 1 million new cases in 2002 worldwide (9.4% of the world total). In terms of incidence, CRC ranks fourth in men and third in women. Mortality is about one half of incidence (about 529,000 deaths in 2002), while prevalence is second only to that of breast cancer worldwide, with an estimated 2.8 million persons alive with CRC diagnosed within 5 years of diagnosis. There is at least a 25-fold variation in occurrence of CRC worldwide. The incidence rates are highest in developed countries, while they tend to be low in Africa and Asia. In Korea, CRC cancer became the fourth leading cause of cancer death in 2004 and the age-standardized incidence rates of CRC in both sexes are higher than world average rates. These geographic differences are probably due to genetic background as well as environmental factors since CRC is one of multifactorial diseases; environmental and genetic factors interact and may work synergistically to develop a disease.
It is known that multiple mutations accumulate during the pathogenesis of CRC. Two major forms of genetic instability in CRC have been classified as either microsatellite instability (MIN) or chromosomal instability (CIN). In about 13% of CRC, mismatch repair deficiency leads to MIN, whereas in the remaining 87%, CIN appears to result in gains and losses of genetic materials. So, characterization of CIN may help to identify potential oncogenes and/or tumor suppressor genes and furthermore elucidate the pathogenesis of CRC.
To characterize CIN, conventional comparative genomic hybridization (CGH) has been used to identify multiple chromosomal imbalances in a sample from a single experiment. However, resolution of the conventional CGH is insufficient for precise identification of sub-microscopic changes. As accumulated evidence suggests that changes in genomic dosage contribute to tumorigenesis by altering the expression levels of cancer-related genes, more detailed analyses with high resolution are necessary.
There is thus a need for an improved diagnostic method.
The information disclosed in this Background section is only for enhancement of understanding of the background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art that is already known to a person skilled in the art.